Drill shaft for strike drilling, esp. into rock - provided with headpiece and bar sections that lose less rotation force transfer as they wear away

摘要

Drill shaft (10) for strike drilling, comprises headpiece (12) for insertion into a drill cap for a rock drilling machine, and a radially projecting collar (14, 14') that connects with the drill cap and separates. the headpiece (12) from a bar section (16) of the shaft (10). The headpiece (12) has a number of lengthways extending, essentially straight concave sections (18) sepd. in the circumferential direction, and a corresponding number of convex sections (20) that bridge the concave sections (18). The bar section (16) has a circular or polygonal cross-section which is incorporated into the cross-section of the headpiece (12).